import React, { Component } from 'react';
import {
  AppRegistry,
  StyleSheet,
  Text,
  View,
  Animated,
  Image,
  Easing
} from 'react-native';

const IMG_URI = 'https://s3.amazonaws.com/media-p.slid.es/uploads/alexanderfarennikov/images/1198519/reactjs.png';

export default class AnimationTing2 extends Component {
  constructor(props) {
    super(props);
    //使用 ** Animated.Value** 声明了一个 spinValue 变量，并传了一个 0 作为初始值
     this.animatedValue = new Animated.Value(0);
  }
  animate () {
       this.animatedValue.setValue(0);//this.spinValue 重置成 0
       Animated.timing(
              this.animatedValue,
         {
             toValue: 1,//终值
             duration: 4000,//一次动画的持续时间
             easing: Easing.linear,//缓存函数
             delay: 0 //延迟执行的时间
         }
      ).start(() => this.animate());
      //调用 start()，并将 this.spin 作为回调传递给 start，它将在(一次)动画完成之后调用，这也是创建无穷动画的一种基本方式
  }
  componentDidMount() {
       this.animate();                         // 开始执行动画
  }

  render () {
               //inputRange 和 outputRange 参数给interpolate 方法，并分别赋值为 [0,1] 和 &[‘0deg’, ‘360deg’] 例 将数值 01 映射到了 0deg360deg
         //将这个值插入到 opacity、margins、text sizes 和 rotation 等样式属性中
         //平移 没有返回 
         const marginLeft = this.animatedValue.interpolate({
               inputRange: [0, 1],
               outputRange: [0, 300]
         });
         //透明度渐变
         const opacity = this.animatedValue.interpolate({
           inputRange: [0, 0.5, 1],
           outputRange: [0, 1, 0]
         });
         //平移 有返回 
         const movingMargin = this.animatedValue.interpolate({
           inputRange: [0, 0.5, 1],
           outputRange: [0, 300, 0]
         });
         //字体大小渐变
         const textSize = this.animatedValue.interpolate({
           inputRange: [0, 0.5, 1],
           outputRange: [8, 32, 8]
         });
         //沿x旋转 
         const rotateX = this.animatedValue.interpolate({
           inputRange: [0, 0.5, 1],
           outputRange: ['0deg', '180deg', '0deg']
         });
         return (
             <View style={styles.container}>
               <Animated.View
                 style={{
                   marginLeft,
                   height: 30,
                   width: 40,
                   backgroundColor: 'red'}} />
               <Animated.View
                 style={{
                   opacity,
                   marginTop: 10,
                   height: 30,
                   width: 40,
                   backgroundColor: 'blue'}} />
               <Animated.View
                 style={{
                   marginLeft: movingMargin,
                   marginTop: 10,
                   height: 30,
                   width: 40,
                   backgroundColor: 'orange'}} />
               <Animated.Text
                 style={{
                   fontSize: textSize,
                   height: 50,
                   width: 400,
                   marginTop: 10,
                   color: 'green'}} >
                   Animated Text!
               </Animated.Text>
               <View></View>
               <Animated.View
                 style={{
                   transform: [{rotateX}],
                   marginTop: 50,
                   height: 100,
                   width: 100,
                   backgroundColor: 'black'}}>
                 <Text style={{color: 'white'}}>Hello from TransformX</Text>
               </Animated.View>
               <View></View>
             </View>
         );
    }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    paddingTop: 150,
    marginLeft: 10,
  }
});





